Tissue culture methodologies allow physiological reactions and occurrences to be studied outside the organism without the influence of other biological reactions.
The incubation of tissue slices for short periods (hours) was introduced for biomedical studies in 1923 by Warburg. Prolonged incubations (days/weeks) were, in practice, not possible until the fifties, following the introduction of antibacterial and antifungal antibiotics.
For any tissue culture methodology to achieve maximum usefulness as a research tool, there must be uniformity between each individual tissue sample which yields uniformity and reproducibility between each separate experiment. However, in the past the production of homogeneous tissue slices from fresh tissue samples has been difficult and very dependent on the skill and experience of the technician. Past attempts to produce tissue samples which are uniform in dimension has been met with a host of problems including irreproducibility of slice thickness, contamination of tissue samples and irregular, nonreproducible trauma to the tissue adjacent to the cutting surfaces. In particular, no tissue slicer of the past has been designed to operate aseptically. In addition, a mechanical method of attachment of the blade to the blade holder which necessitated frequent tightening of the screws or clamps holding the blade in position was utilized. Consequently, the tissue sample became contaminated and inconsistencies in the geometry of the slices and irregular damage to the surfaces resulted from vertical movement of the blade. Also, in the past, tissue slicers have not limited the exposure of the uncut sample surface of the tissue sample to the blade. This unlimited exposure of the tissue sample to the blade resulted in unnecessary and harmful contact of the sample surface with the blade. Because of the above problems many investigators have not turned to tissue culture methodology. This has resulted in under utilization of a technique which is less expensive, reduces the number of experimental animals used, and with which experiments can be performed using human biopsy tissue samples, surgical resection or organ donation samples, with results that avoid the need for questionable extrapolation of results from animals to humans.
My invention enables an inexperienced technician to prepare, rapidly, tissue slices of nearly identical dimensions in an aseptic environment of defined composition and temperature while minimizing tissue trauma. The present invention accomplishes the above by holding the blade in the blade holder by a combination of two pins to limit the lateral displacement of the blade and one or more permanent magnets which provide a constant downward pull on the blade and the blade holder without impeding the reciprocation of the latter. This design eliminates the need for readjustment or tightening during use; therefore, opportunities for contamination are decreased, reproducibility of dimensions is increased and trauma to the tissue resulting from vertical "chatter" of the blade is decreased. Further, the present invention guards the blade to limit the exposure of the tissue sample to the blade to decrease the extent of trauma to the cut surfaces of the slices.